[FFmpeg-cvslog] avformat: prevent triggering request_probe assert in ff_read_packet

[Andreas Cadhalpun]

ffmpeg | branch: release/3.1 | Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com> | Wed Oct 19 19:23:49 2016 +0200| [d69dc10466e234c0e4ff9cb7e4d0e5d63ceeb357] | committer: Andreas Cadhalpun

avformat: prevent triggering request_probe assert in ff_read_packet

If probe_codec is called with pkt == NULL, it sets probe_packets to 0
and request_probe to -1.
However, request_probe can change when calling s->iformat->read_packet
and thus a probe_packets value of 0 doesn't guarantee a request_probe
value of -1.
In that case calling probe_codec again is necessary to prevent
triggering the assert.

Reviewed-by: Michael Niedermayer <michael at niedermayer.cc>
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>
(cherry picked from commit a5b4476a602f31e451b11ca0c18bc92be130a50e)
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=d69dc10466e234c0e4ff9cb7e4d0e5d63ceeb357
---

 libavformat/utils.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavformat/utils.c b/libavformat/utils.c
index 8dc287f..3617449 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -770,7 +770,7 @@ int ff_read_packet(AVFormatContext *s, AVPacket *pkt)
                 return ret;
             for (i = 0; i < s->nb_streams; i++) {
                 st = s->streams[i];
-                if (st->probe_packets)
+                if (st->probe_packets || st->request_probe > 0)
                     if ((err = probe_codec(s, st, NULL)) < 0)
                         return err;
                 av_assert0(st->request_probe <= 0);